Foto de stock - Dog handler Ralf Blechschmidt holds an odour sample to the nose of the bloodhound Hermine during a presentation for the press in Leipzig, Germany, 11 January 2018. Hermine is applied as a so called 'man-trailer dog' during police investigations. A two-year long study of the Institute for Forensic Medicine at university of Leipzig and the Saxony Police's college could prove that man-trailer dogs can be used not only to track human sweat, but that isolated DNA can be an accurate key stimulus for them as well. Researchers worked two years on the project. Over 670 tests were passed by seven dogs. Photo: Hendrik Schmidt/dpa-Zentralbild/dpa. - Leipzig/sax/Germany